Due to diseases of different kinds it is sometimes necessary to remove the larynx by surgery and to open a tracheostoma in order that the individual exposed to the surgery can breathe. By the removal of the larynx the ability to speak will be lost but can be restored to some extent by means of another surgery wherein a fistula is opened up between trachea and esophagus to pass air to the oral cavity via the fistula. A oneway valve is mounted in the fistula. This valve referred to as a voice prosthesis, allows air to pass from trachea to esophagus but blocks completely flow in the opposite direction.
For speech to be generated the tracheostoma must be closed so that air can be pressed from trachea via the voice prosthesis into esophagus the mucous membranes of which are made to vibrate so that speech is produced. The tracheostoma can be closed by covering the tracheostoma with a finger but it is more convenient to use for this purpose a tracheostoma valve of the kind referred to above, which is attached to the neck of the person that has been exposed to tracheostoma surgery, in order to control the connection between trachea and the ambient atmosphere via the tracheostoma.
U.S. Pat. No. 4,582,058 describes a tracheostoma valve wherein the function of the shutoff valve member is controlled by spring bias. This tracheostoma valve requires a relatively high pressure in the housing for keeping the shut-off valve in the closed position during speech, which means that it may be difficult to terminate a sentence when the expiration air from the lungs is ebbing due to the fact that the shut-off valve is unintentionally opened too early. Also, this device is unsuitable for exercising, it comprises a vast amount of components making the manufacturing process difficult and costly, and it has no manual occlusion feature.
U.S. Pat. No. 5,059,208 discloses a patient adjustable valve to control the flow of air through an opening surgically created in the neck of the patient. This device is unsuitable for exercise, since it will close unintentionally when you exhale rapidly. Also, this device has no manual occlusion feature.
WO 01/89618 discloses a tracheostoma valve adapted to control the flow of air through a tracheostoma. The device has a separate adjustable coughing valve with permanent magnets. One of the disadvantages of this device is that it is difficult to close the tracheostoma valve by rapid exhaling, such as when the user is too tired to exhale with sufficient closure rate. Also, this device has no manual occlusion feature. Another problem is that it may be difficult to close the tracheostoma valve when the adhesion between the tracheostoma valve plaster and the skin decreases. Yet a disadvantage is the production cost, resulting from the use of several and expensive parts, such as the permanent magnets. Additionally, this device is noisy, due to the change of air direction in the device.